222 MR. G. A. BOULENGER ON 



Bitis gabonica Bouleng. t. c. p. 499. 



Vipera rhinoceros Bocage, Herp. Ang. p. 149. 



Tropical Africa. 



5. Bitis nasicornis. 



Coluber nasicornis Shaw, Nat. Miscell. iii. pi. xciv. 



Bitis nasicornis Bouleng. t. c. p. 500. 



Tropical Africa. 



3. Atheris. 



Cope, Proc. Ac. Philacl. 1862, p. 337; Bouleng. Cat. Sn. iii. 

 p. 508. 



Two species : — 



Scales in 15 to 25 rows ; gular scales strongly keeled A. squamiger. 



Scales in 25 to 32 rows ; gular scales smooth or very feebly keeled... A. nitschei. 



, 1. Atheris squamiger. 



Echis squamigera Hallow. Proc. Ac. Philacl. 1854, p. 193. 



Atheris squamiger Bouleng. t. c. p. 509 ; Bocage, Herp. Ang. 

 p. 152. 



West Africa, from Calabar to Angola, Central Africa and 

 Uganda. 



2. Atheris nitschei Tornier, Zool. Jahrb., Syst. xv. 1902, 

 p. 589, fig. 



Atheris woosnami Bouleng. Ann. & Mag. N. H. (7) xviii. 1906, 

 p. 37. 



Belgian Congo, N.W. of L. Tanganyika, Mt. Ruwenzori, 

 western parts of German East Africa. 



4. Atractaspis. 



A. Smith, III. Zool. S. Afr., Rept. ; Bouleng. Cat. Sn. iii. 

 p. 510. 



Synopsis of the Species. 



I. Anal divided ; all or most of the subcaudals paired ; snout rounded. 



A. Second lower labial separated from its fellow by the chin-shields. 



Scales in 19 to 21 rows ; ventrals 200-235 A. congica. 



Scales in 23 to 27 rows; ventrals 217-257 A. irregularis. 



B. Second lower labial forming a suture with its fellow ; 



scales in 21 to 23 rows; ventrals 336-356 A. lieterochilus. 



II. Anal entire; all or most of the subcaudals single. 

 A. Postocular in contact with a large temporal. 



1. First lower labial forming a suture with its fellow behind the symphysial. 



Snout very prominent, cuneiform ; second lower labial very 

 large, forming a suture with its fellow ; scales in 23-27 

 rows; ventrals 178-193 A. corpulenta. 



Snout prominent, subcuneiform ; third lower labial very 



large ; ventrals 221-260 A. bibronii. 



